"Scientists have had a string of remarkable successes lately, taking signals from the brains of monkeys and men, and using them to move mechanical arms.

Darpa, the Pentagon's blue-sky research division, now wants to ratchet that work up about ten notches, by developing a "neurally controlled artificial limb that will restore full motor and sensory capability to upper extremity amputee patients. This revolutionary prosthesis will be controlled, feel, look and perform like the native limb."

So, basically, what Luke Skywalker gets in Empire Strikes Back, after Darth chops off his hand. Except, researchers won't have a long, long time to get this limb ready. Darpa wants the robo-arm stat -- in four years or less.

The limb would have to be wired directly into the peripheral nervous system, instead of the brain-controlled arms being demonstrated today..."